On Wed, 2 May 2007, Customer Support wrote:
> smart_route:
> driver = manualroute
> domains = !+local_domains
> transport = remote_smtp
> route_list = * "${lookup mysql{SELECT target FROM exim_smarthost
> WHERE (domain='$domain')}}"
>
> According to the documentation the destination of a route list can
> include a server and port.
> I've tried setting target to
> domain.com:2525
> and bearind in mind exim uses : to split host names, I've tried
> domain.com::2525 as described in another document.
>
> Anyone got any ideas as to how I can specify a target host and port
> for the forwarding?

The manual has the explicit example

route_list = * "host.tld::1225"

Have you got debugging information to show that this does not work?
Which release of Exim? Support for ports in manual route was added at
release 4.53.